The truth about B12 and where to get it on a vegan diet

Read Time:   |  13th May 2020

It’s simply not true that vegans need to take handfuls of supplements to stay healthy, but we do all need to make sure we are getting enough vitamin B12. Here's what you need to know as well as the vegan B12 sources to make sure you're getting enough.

Although a plant-based diet provides our bodies with almost everything they need to thrive, vegans must take vitamin B12 supplements.

Read on to find out why this is and the best sources of B12 for vegans.

How do we get vitamin B12 on a vegan diet?

Vitamin B12 is made naturally by bacteria in the soil. Traditionally, people and animals would have obtained this vitamin by eating food from the ground.

However, food production systems are now so sanitised and scrubbed clean that we do need to take a supplement.

Animals are no different to us and are not magical creators of vitamin B12. Meat, eggs and dairy foods contain it because farmed animals are given supplements too – their natural diet having been depleted1 in much the same way as our own.

The argument to eat meat and dairy for B12 is therefore invalid — so why not get your B12 straight from the source?

Why do we need it and what are signs of B12 deficiency?

B vitamins help our bodies release energy from the food we eat. Vitamin B12 also helps maintain healthy nerve cells and produces DNA — our genetic material2.

It works closely with folic acid to make red blood cells, which help iron to work better in our bodies. It also helps our immune systems to function normally and can even affect our mood.

Signs of deficiency include extreme tiredness, lack of energy, pins and needles, muscle weakness, depression and cognitive problems, such as impaired memory, understanding and judgement3.

Anaemia can occur when a lack of B12 or folate affects our body’s ability to produce enough red blood cells.

A lack of B12 can also lead to a raised blood levels of an amino acid called homocysteine which, at high levels, is linked to heart disease.

What is the recommended intake of vitamin B12?

We need only a little B12, and the government’s recommended intake is 1.5mcg a day (a microgram is a millionth of a gram), but getting that small amount is vital.

US guidelines are slightly higher, at 2.4mcg, and the European Food Safety Authority suggest an ‘adequate intake’ of 4mcg a day.

Some studies4 suggest that vegans have lower B12 levels than people who eat meat and dairy, but many studies have only included B12 from food and ignored intake from supplements.

The UK National Diet and Nutrition Surveys have found low vitamin B12 levels are not uncommon5 among the general population, regardless of diet, especially in people over 50. The reason is that absorption is a complicated process that declines with age.

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Why does our absorption of B12 decline?

In order to absorb B12, it must first bind with a protein produced in the stomach called intrinsic factor. If you don’t make enough of this protein, you may not be able to absorb sufficient B12, even if your diet is awash with it.

Another reason absorption declines with age is because the amount of stomach acid we make can also drop as we get older.

The B12 from meat is bound to animal protein so stomach acid is needed to release it before it can be absorbed6. The B12 in fortified foods and supplements is not bound in this way and so is easier to absorb.

Absorption can also be reduced by poorly functioning kidneys, the diabetes drug Metformin and proton pump inhibitors, nitric oxide in cigarette smoke and nitrous oxide (NOS or laughing gas).

In the US, all adults over 50 are advised to obtain their B12 from supplements or fortified foods because of the high numbers of people in this age group who have a reduced ability to absorb it from animal foods.

Vegans have an advantage if they routinely include fortified foods and supplements in their diet.

Vitamin B12 is a water-soluble vitamin, so what you don’t need is excreted in your urine. Excessively high doses could be harmful but government guidelines say that taking up to 2,000mcg a day is unlikely to cause harm.

What are the best sources of vitamin B12?

This vitamin can be lost in cooking, so heating B12-fortified plant milk in a microwave, for example, can destroy the B12 in a couple of minutes.

On a hob or steaming, the milk would have to be at or near boiling point for five to seven minutes to destroy a significant amount.

The best plant sources of B12 include yeast extract (Marmite/Vegemite) and B12-fortified foods such as nutritional yeast flakes, plant milks, vegan yoghurts and desserts, breakfast cereals and margarine.

The body can store B12 for two to four years without being replenished so it can take a considerable time for any problems to develop after, say, changing your diet. Having said that, you should not rely on your body’s stores of B12.

Should vegans supplement vitamin B12?

Levels can be easily checked by a doctor and any deficiency can be treated with supplements or a course of injections. It’s important not to ignore your intake of B12 as by the time any symptoms develop, the damage may have already occurred.

Should you take a supplement? Yes. Vegan health bodies recommend consuming fortified foods with a regular use of a supplement — particularly for children.

This, and a well-planned and varied vegan diet, will meet your requirements and provide a healthier and safer source of vitamin B12 than obtaining it from animal products.

Fortified Food Guide

Micrograms of vitamin B12

(recommended amount = 1.5 micrograms per day)

Meridian Yeast Extract

4g serving (enough for one slice of toast)

vegan sources of b12

Engevita Yeast Flakes

5g serving (sprinkle on pasta, beans, etc)

vegan sources of b12


8g serving

vegan sources of b12

Weetabix Weetaflakes*

30g serving

vegan sources of b12

Vecon Vegetable Stock

1 tsp (5g serving)

vegan sources of b12

Alpro Desserts & Yoghurts

125g pot

vegan sources of b12

Koko Dairy Free Yoghurt

125g pot

Weetabix Oatbix Flakes*

30g serving

Violife Chicken Slices

28g serving (2 slices)

Plant-Based Milk Alternatives Fortified with B12

One glass (250ml)

Violife Cheese Slices

40g serving (2 slices)

*Many cereals fortified with B12 also contain vitamin D (D3) from lanolin, a substitute obtained from sheep’s wool. At the time of writing, Weetabix Weetaflakes and Oatibix Flakes contain  B12 and no Vitamin D, so are suitable for vegans. This can change, and often does, so do read the ingredients list on the packet when you buy cereal.


  4. Gilsing, AMJ, Crowe, FL, Lloyd-Wright, Z, Sanders, TAB, Appleby, PN, Allen, NE, Key, TJ. Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians and vegans: Results from a cross-sectional analysis of the EPIC-Oxford cohort study. Eur J Clin Nutr. 2010; 64 (9):933-9


Written by

Dr. Justine Butler

Dr. Justine Butler

Viva! Health is a part of the charity Viva!, Europe’s largest vegan campaign group. It monitors scientific research linking diet to health and provide accurate information on which you can make informed choices about the food you eat.

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